Tea is one of the most popular beverages in the world, and drinking it is thought to provide various health benefits.

In Great Britain and some other parts of the world, tea is commonly consumed with milk.

However, it’s unclear whether adding milk to tea provides additional benefits or instead interferes with the activity of tea compounds in your body.

This article provides an overview of the effects of adding milk to tea.

Both tea and milk provide benefits
While several kinds of tea may provide health benefits, green and black teas are the most researched.

Both are made from the leaves of the Camellia sinensis plant but undergo different processing methods.

Green and black teas are rich in plant compounds called flavonoids. These compounds act as antioxidants to help fight underlying cell damage caused by reactive molecules known as free radicals. High levels of free radicals contribute to heart disease, cancer, and other issue.

Specifically, green teas are rich in flavonoids called catechins, while black teas have high amounts of theaflavins.

Due to these compounds, drinking green and black tea has been associated with lower blood pressure, anticancer effects, and reduced cholesterol levels in both animal and human studies.

On the other hand, milk is rich in nutrients, such as protein, calcium, and potassium, that are vital for optimal growth, body composition, and bone health.

Milk proteins may interfere with tea compounds, but research is mixed
Given that both tea and milk contain health-promoting compounds and nutrients, combing the two may seem beneficial.

In fact, one study in over 1,800 adults in China found that both tea and milk consumption were independently linked to a lower risk of oral cancer and that they may have a particularly beneficial effect when consumed together.

Yet, some studies suggest that the proteins in milk may interfere with the absorption and antioxidant activity of the compounds tea.

One study in 16 adult women observed that drinking 2 cups (500 ml) of plain black tea significantly increased blood flow, which can help improve heart function, compared with drinking water. Meanwhile, drinking black tea with skim milk did not have these effects.

The researchers concluded that casein, a type of protein in milk, may bind to flavonoids in tea and prevent their activity in the body.

However, another small study in 9 adults noted that consuming black tea increased blood levels of antioxidant flavonoids and that adding milk to tea did not inhibit this effect

Interestingly, the researchers suggested that longer brewing times may lead to better absorption of the antioxidants in tea, regardless of the addition of milk.

Based on the conflicting results of these studies, milk may interfere with the activity of antioxidants in teas to some extent, but it may not have the same effect with teas that have been infused for long periods.

However, more research is needed to better understand the potential benefits and downsides of adding milk to tea.